Serious spinal cord injuries (SCI) affect approximately 1.3 million people in the United States, and roughly 12-15,000 new injuries occur each year. Of these injuries, approximately 50% are complete spinal cord injuries in which there is essentially total loss of sensory motor function below the level of the spinal lesion.
Neuronal networks formed by the interneurons of the spinal cord that are located in the cervical and lumbar enlargements, such as the spinal networks (SNs), can play an important role in the control of posture, locomotion and movements of the upper limbs, breathing and speech. Most researchers believe that all mammals, including humans, have SNs in the lumbosacral cord. Normally, the activity of SNs is regulated supraspinally and by peripheral sensory input. In the case of disorders of the connections between the brain and spinal cord, e.g., as a result of traumatic spinal cord lesions, motor tasks can be enabled by epidural electrical stimulation of the lumbosacral and cervical segments as well as the brainstem.